InChI=1S/C16H20O4/c1-8(2)14-13(17)11-6-5-10-7-9(3)19-16(18-4)12(10)15(11)20-14/h5-6,8-9,14,16H,7H2,1-4H3/t9-,14?,16+/m0/s1